A) Field of the Invention
This invention relates to recording of new data to an optical disc in a state of no further writing by a finalizing process and reproduction of the recorded data.
B) Description of the Related Art
In recent years, prices for a data-recordable optical disc, an optical disc recording/reproducing apparatus, software for data recording, a computer and the like are decreasing. Also, the optical disc is a medium to which a large capacity of data can be recorded. Therefore, the optical disc is widely used for recording/reproducing and backup various data such as audio (musical) data, data for computer, image data, motion picture data and the like. As a data recordable optical disc for recording, for example, there are a write-once optical disc to which data can be recorded only once such as a CD-R and a DVD-R and a re-writable optical disc to which data can be rewritten such as a CD-RW, a DVD-RW, a DVD+RW and a DVD-RAM. In these optical discs, currently the CD-R and the CD-RW are particularly popular.
In a case that information is recorded to the CD-R/RW, the recording is executed in accordance with a format provided by a CD-DA standard, a CD-ROM standard and a multi-session CD standard corresponding to data to record in order to maintain a compatibility. Also, in the case that data is recorded to the optical disc in accordance with the above standards, it is provided to record by a unit called a session that is a lead in area, a program area and a lead out area as one unit. The optical disc that recorded with formats of the CD-DA standard and the CD-ROM standard (single session) equips one session for one optical disc and is also called a single session CD. Also, the optical disc recorded with the format provided by the multi session CD standard equips a plurality of sessions for one optical disc. In this case, the standard provides to set one minute thirty seconds for the lead out area in a first session, and one minute for the lead in area and thirty minute for lead out area after a second session.
FIG. 10 is a diagram showing a data structure of the optical disc, and FIG. 10A is a diagram of a state of a CD-R without any recorded data (i.e., a blank disk). In a recording area, a starting point to write information and a maximum outer edge position of the lead out area are fixed. That is, a starting position of the program area is φ50 mm, and a starting position of a last possible lead out (LLO) time is φ116 mm. Also, when these starting position are presented in time information, the starting position of the program area is 00m:00s:00f, and the starting position of the LLO is 79m:59s:74f in the case of an optical disc with a capacity of 70 MB. The “m”, the “s” and the “f” are abbreviations of minute, second and frame.
Also, the inside from the starting position of the program area is an area that is set as the lead in area, and identity information of the blank disk uses a cycle change of a wobble of a guiding groove to record as an absolute time in pregroove (ATIP). The cycle of the guiding groove is a FM modulation of the ATIP information, and LLO information can be acquired as a disk capacity from the ATIP information.
FIG. 10B is a diagram in the case that the finalizing process is executed by recording CD-DA standard (music CD) information. A table of contents (TOC) information is recorded in the lead in area, and in the case that a plurality of tracks are recorded in the program area, a starting time (position information) and a starting time of the lead out area of each track are recorded in the TOC as a contents information. Further, in this case, the standard provides to set one minute thirty seconds for the lead out area in order to record data as the first session.
FIG. 10C is a diagram in the case that the finalizing process is executed by recording CD-ROM standard (data for a computer) information. However, it is a similar session structure as FIG. 10B, the program area is only a track 1, and a starting time (index information) of the track 1 and the starting time of the lead out area are recorded in the TOC. Also, actual index information is recorded in a beginning part of the program area.
FIG. 10D is a diagram of the case of the multi session and shows the case that the finalizing process is executed in a third session. Since the finalizing process is not executed after recording the first session and the second session, further writing of the second session and the third session is possible. However, since the finalizing process is executed in the third session, data cannot be written further after that.
Writing method of data to the optical disc is roughly classified into two, a disk at once (hereinafter called DAO) and an incremental write. Also, there are three kinds of methods in the incremental write, and they are a track at once (hereinafter called TAO), a session at once (hereinafter called SAO) and a packet write.
The DAO is a method for writing the whole CD from the beginning at a time in a sequence of lead in, data and lead out. Further, in this method, when data is written once, further writing of data cannot be executed after that.
The TAO is a method for writing each track, and an actual writing is executed in a sequence of data, lead in and lead out. In this method, writing is executed one by one track, and after finishing writing of all tracks, a close session can be executed.
The SAO is a method for writing by a session. When this method is used, a plurality of sessions can be recorded in one optical disc, and a multi session CD can be made.
The packet write is a writing method only for computer that can execute further writing by a file.
In the case that data is recorded in a further writing type optical disc by the above described each method, data writing is executed with an optical disc reproducing apparatus by using a writing soft installed in a computer. FIG. 11 is a diagram showing the finalizing process by the writing soft. FIG. 11A is a diagram showing a process to make the optical disc no further writing. When an option “close the CD (make no further writing)” of the writing soft is checked, recording executed after that is finished to execute the close session, and a disk close is executed, and the further writing type optical disc becomes to be in a state of no further writing and cannot execute any writing after that. That is, the further writing type disk cannot revise the recorded data.
FIG. 11B is a diagram showing a process for enabling further writing to an optical disc. On the other hand, when an option “close the CD” of the writing soft is not checked, session can newly be written after that because the disk close is not executed; however the recording to be executed is terminated to execute close session.
A difference between these operations is according to a difference of the information of the lead in area at a time of recording data. That is, the TOC information is recorded as sub code information in the lead in area, and when an item in the multi session information is “ADR=5, TNO=0, POINT=$B0”, the information shows that the disk is multi-session. Also, other item shows the starting time of the program area and the starting time of the leading out (LO). Further, when the disk is not multi-session, there is not “ADR=5, TNO=0, POINT=$B0” in the sub code information. Therefore, by distinguishing the above information, the optical disc reproducing apparatus can judge either there is more session the outer session or the session is the last session (the last session).
As the above, after a data is recorded with a setting to prevent further writing (recording further writing preventing information) by executing the finalizing process when the data is recorded by each method of the incremental writing, further writing will be impossible. Therefore, however it is effective in the point of preventing data revision, data cannot be added in the case that recorded data is less and a large vacant capacity is remained. Therefore, it is a problem that the free space of the optical disc is useless.
On the other hand, there is a CD extra (or also called CD+) standard as the multi-session CD standard. FIG. 12 is a diagram showing a data structure of the CD extra. The optical disc recorded in accordance with this standard has two session structure of the first session and the second session as shown in FIG. 12. That is, the first session is the CD-DA and records music, voice and the like. Also, the second session is the CD-ROM and records data such as data for computer, image, text and the like.
The CD extra with this recording format can executing further writing data for computer in the second session after recording the musical data recorded in the first session. However, in the case that data is recorded with the CD extra standard, when data is recorded in the second session to execute the finalizing process, it is the problem that data cannot be written further after that in this method, too.
Also, since the CD extra is a multi-session CD, in the sub code of thee lead in area of the first session, there is “ADR=5, TNO=0, POINT=$B0”. However, a CD player manufactured in accordance with only the CD-DA standard can reproduce only the CD-DA and does not support the multi-session. Therefore, when “ADR=5, TNO=0, POINT=$B0” is presented in the sub code of the lead in area of the first session, the CD player ignores it (cannot recognize it). Therefore, the CD player reproduces only the first session, the CD-DA part, to finish, and does not reproduce the second session.
On the other hand, a CD-ROM device connected to a computer that supports multi-session and a player only for the CD extra can reproduce the first session and the second session of the CD extra.
Therefore, the second session of the CD extra is hidden data that cannot be read out for the CD player. However, since the second session of the CD extra can be reproduced easily by the CD-ROM device and the player only for the CD extra, it is not hidden data for these devices.